1. Field of the Invention
The present invention relates to a rotary-to-linear motion conversion mechanism for converting the direction of motion between rotary motion and linear motion.
2. Description of the Related Art
As a rotary-to-linear motion conversion mechanism, there has been known one wherein a rod having a thread at its outer peripheral surface, a holder member provided on the outer peripheral surface of the rod and provided so as to be rotatable relative to the rod and axially movable relative thereto, and a plurality of rollers supported rotatably by the holder member and having annular grooves which mesh with the thread of the rod at their outer peripheral surfaces, are disposed aslant with respect to the central axis of a holder, and the rotation of each roller is converted into linear motion of the rod by meshing engagement therebetween.
The rotary-to-linear motion conversion mechanism is, however, accompanied by problems that upon assembly thereof, since the rollers are different from one another in the tilt direction with respect to the holder, a difficulty occurs in fixing one end sides thereof to the holder and thereafter making fixation for the other end sides. On the other hand, there has been proposed a method such as turning only the ends of the rollers into tilt-free forms (refer to U.S. Pat. No. 3,101,623).